This invention relates to a package for an improved programming and control device for a modified lead ballast for HID lamps and particularly for HID sodium lamps and to a luminaire which incorporates such a packaged device.
The basic modifying device for a lead-type ballast is disclosed in the aforementioned copending application Ser. No. 414,114, filed concurrently herewith. In its preferred form, a series-connected additional inductor and a gate-controlled AC switch are connected in parallel across the capacitor of the lead ballast and a sensing and programming means operates to sense at least one lamp operating parameter in order to control the proportion of time the AC switch is opened and closed, which varies the current input to the lamp. An improved control device which has been specifically tailored to operate with such a basic modifiying device is disclosed in copending application Ser. No. 414,115, filed concurrently herewith by J. C. Engel.
The most common ballast which is utilized in the U.S. with HID sodium lamps is the so-called lead ballast. The basic components of such a ballast comprise a high reactance transformer with a capacitor connected in series between the transformer secondary and the lamp to be operated. The capacitor is normally contained within a can-shaped member with exposed terminals for ready connection in circuit. Most luminaires which incorporate such a lead-type ballast are fabricated so that space is provided for an additional capacitor. Recent improvements in capacitors, however, have obviated the need for a second capacitor. Because of its location within the luminaire, an additional electrical member, if used, can be readily connected in circuit if it is positioned within the available but unused space provided for the second ballast capacitor.